In your original thread you talked about tank size, tank size and tank size and a lot about gallons also and little else. You said the next size you were looking at was 120 GAL as if that meant a big compressor. You said you were lacking in room but you were going to sacrifice some of it to make room for the big tank and even add a second tank if you could find room. You also said you were aiming for the most gallons you could get. Why? That is why I said you were almost overlooking what really matters. A 60 gallon vertical tank is just fine for a small shop and is all you need and would not take up as much room as a big 120 horizontal unit and the second tank is unnecessary. The compressors you mention are good sized units and will provide enough air for most shops regardless of which tank you get. You said that although the 80 gal tank will take up a lot of room it will be worth it, but will it? The only difference you will see between a 60 gal and an 80 gal is that the compressor will not cycle on and off as often but it will run longer when it it does kick on but it will not make the compressor deliver more air. When using a high volume tool like a DA sander these cycle time differences can usually be measured in seconds and it would be a mistake to sacrifice needed room for an over-sized tank thinking it will increase compressor performance when it will not. Clearly you were looking at the tank as the most important factor when in reality it is the least important part of the system and in fact the compressor would deliver the same amount of air with a 40 gal tank as it would with a 120 gal. A tank that small would cause other problems and I am only using that to make the point that going to the extreme either way is not good.